2011 Vermont Residential Building Energy Standards

I recently attended a educational session on the 2011 Vermont Residential Building Energy Standards (RBES). One key point that came up during this presentation is that while the 2011 RBES is still in draft form, state statute requires them to be in effect by January 1, 2011. This discrepancy is creating some confusion as to which standards are currently in effect. That aside, I would like to go into some of the key features of the revised RBES.

The RBES is based on the 2009 International Energy Conservation Code. The key areas of compliance are:

• Insulation
• Envelope Air Leakage
• Duct Leakage
• Ventilation and Combustion Safety
• Efficient Lighting

For insulation there are three methods of determining compliance. The first and easiest method is through the minimum R-value of each assembly. The are certain prerequisites necessary to use this method such as maximum amounts of glazing and construction types. Typical R-values for the assemblies would be Ceilings R-49, Walls R-20 or R-13 plus continuous R-5 sheathing, Floors R-30, Basement Walls R-20 or R-15 continuous, Slabs R-15; the maximum U-value for windows is U .32. REScheck software is the second method of compliance and allows for greater flexibility with a minor increase in the complexity of determining compliance. The final method of compliance is through the use of a building energy model. This method offers the greatest flexibility, but with the greatest complexity.

Air leakage offers two methods of compliance. The first requires compliance with a checklist of items that need to be air sealed. The other is conducting a blower door test and ensuring that there are less than 5 air changes per hour at 50 pascals.

The duct leakage provisions are only required for heating and cooling ducts. Ducts that are utilized only for ventilation are not required to comply. The provision requires that any duct that penetrates the insulated envelope to comply with the insulation requirements for the assembly that it penetrates. The two easiest ways to comply with this is to 1) provide for heating and cooling in a method that does not require forced hot air 2) keep the ducts with the envelope.

Energy efficient lighting requires that 50% of all lamps are of an energy efficient type, basically either LED's or fluorescent. These bulbs can be of a screw in type and are not required to use a pin connection. The other aspect of this is one programmable thermostat is required. There are some heating systems that are exempt from this, such as for a radiant floor.

One additional important fact about the 2011 RBES is that it applies not only to new construction but also to all additions and renovations. With additions or renovations, this applies only to the areas that are being worked on. However, additions and renovations could impact the ventilation of combustion appliances. So even though the appliances may not be located in the area being work on, they may need to be addressed as well.

UPDATE:

I received the following clarification from the Vermont Legislative Council

"The main answer is that, until the revised RBES are finally adopted by the Dept. of Public Service (DPS), a builder must comply with the existing RBES, and therefore for construction completed prior to the revised RBES the builder would not be subject to a lawsuit regarding compliance with draft changes. Under 21 V.S.A. sec. 266(b), the requirement is to comply with the regulations adopted by the DPS. If there is a need to make a clarification to the law for builders who have commenced but not completed construction by the effective date of the new RBES, that is possible, though it would raise other issues"

UPDATE 7/19/2011:

I received the following clarification from Chris Gordon at VEIC

"After completing a public and legislative review of Vermont’s residential energy code- the Residential Building Energy Standard (RBES)- the State of Vermont recently adopted a new residential energy code on July 1 that will go into effect on OCTOBER 1, 2011 and “shall apply to construction commenced on and after [that] date…”. The State of Vermont Department of Public Service in collaboration with Efficiency Vermont will be providing a series of energy code trainings throughout the state this summer and fall.

Please note that the currently scheduled RBES workshops are designed for builders, contractors, architects, and other building professionals. A separate series of trainings will be scheduled for town clerks and real estate professionals. Trainings on the new Commercial Building Energy Standard (not yet adopted) will be scheduled for the fall.

Visit www.efficiencyvermont.com/for_our_partners/res_nc_partners/training_opportunities.aspx for up to date information on energy code trainings. Newly revised RBES Handbooks will be available in late July/early August at http://publicservice.vermont.gov/energy/ee_resbuildingstandards.html. Handbooks will also be available at trainings and through the Energy Code Assistance Center (855-887-0673).

There are significant changes in RBES as a result of this update. Major changes include, but are not limited to:

• Expansion of RBES jurisdiction to include alterations, renovations, & repair of existing buildings (previously RBES only applied to new construction & additions > 500 sq. ft.)

• Increases in insulation levels that exceed current conventional construction practice

• Basement/crawlspace walls R-15 continuous insulation or R-20 if thermally bridged

• Slab - R-15 slab edge & under slab (under slab insulation required for radiant slabs only)

• Walls - R-20 for 2”x 6” or R-13 (cavity) + R-5 (continuous insulation on exterior) for 2”x 4” walls

• Ceilings – R-49 (with some exceptions)

• Windows – weighted average U-factor of U-0.32 or less

• Explicit & increased requirements for air sealing

• 50% of the bulbs in permanently-installed lighting fixtures must be high efficacy (ex. screw-in CFLs, dedicated pin-based fluorescent fixtures, or LEDs)."